Fracture strength of endodontically treated teeth with flared root canals and restored with different post systems.

BACKGROUND: Many post systems are available to clinicians, yet no consensus exists about which one is better in restoring endodontically treated teeth.

PURPOSE: This study evaluated the fracture strength of teeth with flared canals and restored with two fiber-reinforced resin systems (glass fiber: FRC Postec [Ivoclar Vivadent, Schaan, Liechtenstein]; quartz fiber: D.T. Light-Post [Bisco Dental Products, Schaumburg, IL, USA]), and one custom cast base metal (Ni-Cr) post and core system.

METHODS: Thirty anterior teeth had their crowns removed below the cemento-enamel junction and were endodontically treated. The canals were prepared for post fixation, and the canal walls were flared using a taper diamond bur. The prepared roots were randomly divided into three groups according to the post system. All posts were cemented with an adhesive resin cement. For the fiber-reinforced resin posts, cores were built up using microhybrid composite. Metallic crowns were luted using zinc phosphate cement. Specimens were loaded at 45 degrees in a universal testing machine at a crosshead speed of 0.5 mm/min until failure. The mode of failure was classified as repairable or nonrepairable.

RESULTS: Teeth restored with cast posts had fracture strength twice that of teeth restored with resin posts. Fiber-reinforced resin posts failed at a compressive force comparable to clinical conditions, but all failures were repairable.

CONCLUSION: Fracture strength and mode of failure in anterior teeth with flared canals varied according to the type of post used to support a crown.

CLINICAL SIGNIFICANCE: Under the conditions of this study, cast posts are preferable to restore endodontically treated teeth with flared canals and no ferrule.